Current regulation apparatus

ABSTRACT

A current regulation apparatus is provided. The current regulation apparatus includes a trans unit, a first switching unit, a voltage detection unit, a voltage comparison unit, and a control unit. The trans unit includes an auxiliary winding unit. The first switching unit controls an operation of the trans unit. The voltage detection unit detects a voltage induced to the auxiliary winding unit. The voltage comparison unit compares a voltage detected by the voltage detection and a reference voltage. The control unit adjusts a turn-on section of the first switching unit according to an output voltage of the voltage comparison unit.

TECHNICAL FIELD

The present disclosure relates to a current regulation apparatus.

BACKGROUND ART

Generally, to stabilize an output voltage of a Switching Mode PowerSupply (SMPS), the related art disposes an error detection circuit in anoutput voltage switching unit of a trans unit, detects an error of anoutput voltage with the error detection circuit, and feeds back thedetected error voltage to a power change unit through an opto coupler,thereby controlling the output voltage.

The trans unit changes a current to a current suitable for an LightEmitting Diode (LED) and supplies the changed current to the LED. As adevice for regulating the current of the LED, an opto coupler is beingused.

DISCLOSURE OF INVENTION Technical Problem

A device such as an opto coupler for feedback is expensive, technologyis being researched for manufacturing a power source circuit of a transunit, which does not require a high accuracy of an output voltage, atlow cost.

Solution to Problem

Embodiments provide a current regulation apparatus which regulates anoutput current of a trans unit according to a voltage level that isdetected from an auxiliary winding unit of the trans unit.

Embodiments also provide a current regulation apparatus which detects avoltage from the auxiliary winding unit of a trans unit and compares thedetected voltages, thereby regulating a constant current according tothe change of an input and/or output voltage of the trans unit.

In one embodiment, a current regulation apparatus includes: a trans unitincluding an auxiliary winding unit; a first switching unit controllingan operation of the trans unit; a voltage detection unit detecting avoltage induced to the auxiliary winding unit; a voltage comparison unitcomparing a voltage detected by the voltage detection unit and areference voltage; and a control unit adjusting a turn-on section of thefirst switching unit according to an output voltage of the voltagecomparison unit.

Advantageous Effects of Invention

According to embodiments, the volume of a trans unit can be reduced.

According to embodiments, by adjusting an error of an output voltage ofthe trans unit, an output current can be stably supplied.

According to embodiments, the reliability of a current regulationapparatus for LED can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a current regulation apparatusaccording to an embodiment.

FIG. 2 is a circuit diagram illustrating the current regulationapparatus of FIG. 1.

FIG. 3 is a diagram illustrating a charging operation of a first timeconstant circuit in a turn-on section of a first switching unit of FIG.1.

FIG. 4 is a charging waveform diagram of the first time constant circuitof FIG. 3.

FIG. 5 is a partially enlarged diagram of FIG. 4.

FIG. 6 is a diagram illustrating a discharging operation of the firsttime constant circuit in a turn-off section of the first switching unitof FIG. 1.

FIG. 7 is a discharging waveform diagram of the first time constantcircuit of FIG. 6.

FIG. 8 is a charging and discharging waveform diagram of the first timeconstant circuit of FIG. 2.

FIG. 9 is a detailed circuit diagram illustrating a comparison unit ofFIG. 2.

MODE FOR THE INVENTION

Hereinafter, a current regulation apparatus according to embodimentswill be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating a current regulation apparatusaccording to an embodiment.

Referring to FIG. 1, a current regulation apparatus according to anembodiment includes a filtering unit 11, a rectification unit 13, atrans unit 15, a Direct Current (DC) output unit 17, a light emissionunit 19, a control unit 21, a first switching unit 23, a feedback unit25, and an error voltage detection unit 31.

The filtering unit 11 removes noise included in an input AlternatingCurrent (AC) voltage. The filtering unit 11 may include anelectromagnetic interference (EMI) filter, for example, include acapacitor.

The rectification unit 13 rectifies a voltage outputted from thefiltering unit 11 and supplies the rectified voltage to the trans unit15. The rectification unit 13 includes a bridge diode circuit, whichfull wave-rectifies the voltage outputted from the filtering unit 11 andsupplies the rectified voltage.

An output voltage Vin of the rectification unit 13 is inputted to thetrans unit 15, which outputs a voltage to a secondary side according tothe turn-on of the first switching unit 23. An output voltage Vo of thetrans unit 15 is supplied to the light emission unit 19 by the DC outputunit 17. The DC output unit 17 includes a smoothing circuit, whichsmoothes a voltage necessary for a load and outputs the smoothedvoltage.

The light emission unit 19 includes a plurality of LEDs 19A, which maybe connected in serial or serial-parallel. Herein, the serial-parallelconnection includes a circuit where groups of the serially-connectedLEDs 19A are connected in parallel.

The control unit 21 controls a Pulse Width Modulation (PWM) signal andoutputs the PWM signal through a driving terminal DRV, according tosignals that are respectively inputted through an input terminal CT anda control terminal Ctl. A signal outputted through the driving terminalDRV of the control unit 21 turns on/off the first switching unit 23. Avoltage induced to a primary side of the trans unit 15 is outputted tothe secondary side according to the turn-off of the first switching unit23.

The control unit 21 includes a Power Factor Compensation (PFC) circuit,which regulates a current, based on the change of the output voltage ofthe trans unit 15, without any change. That is, the control unit 2detects an error due to the change of the output voltage of the transunit 15 to controls a duty ratio of the first switching unit 23, therebyregulating a current applied to the light emission unit 19 without anychange.

The auxiliary winding unit 15A of the trans unit 15 is connected to theerror voltage detection unit 31 and the feedback unit 25, and the errorvoltage detection unit 31 and the feedback unit 25 may be respectivelyconnected to both ends of the auxiliary winding unit 15A. However, theembodiment is not limited thereto.

The feedback unit 25 outputs a voltage, detected through the auxiliarywinding unit 15A, to a feedback terminal FB of the control unit 21. Thecontrol unit 21 detects an opened state or overloaded state of the lightemission unit 19 with the voltage detected through the feedback unit 25,and controls the driving of the first switching unit 23 according to thedetected state. Also, a voltage applied to the auxiliary winding unit15A is supplied to a power source terminal Vcc of the control unit 21.

A voltage outputted from the auxiliary winding unit 15A is detected as avoltage proportional to the level of the input voltage Vin or outputvoltage Vo of the trans unit 15.

The error voltage detection unit 31, as illustrated in FIGS. 1 and 2,includes a voltage detection unit 33, a second switching unit 35, and avoltage comparison unit 37. The voltage detection unit 33 is connectedto a first tap of the auxiliary winding unit 15A. The voltage detectionunit 33 charges and smoothes an input voltage or discharges the chargedvoltage, thereby allowing the input voltage to be detected at a constantDC level. A voltage V2 of the voltage detection unit 33 is outputted tothe voltage comparison unit 37 during a turn-off section of the secondswitching unit 35. The voltage comparator 37 compares the voltage V2detected by the voltage detection unit 33 with a reference voltagetherein to output a signal to the control terminal Ctl of the controlunit 21.

The second switching unit 35 and the first switching unit 23 aresimultaneously turned on/off by a driving signal of the control unit 21.

When the voltage V2 detected by the voltage detection unit 33 exceedsthe reference voltage, the voltage comparison unit 37 decreases thelevel of an output voltage V3 of the voltage comparison unit 37. Whenthe voltage V3 inputted to the control terminal Ctl is reduced in level,the control unit 21 adjusts the driving signal so as to shorten aturn-on section of the first switching unit 23. Therefore, an outputcurrent of the trans unit 15 is decreased in proportion to a decreaserate of the turn-on section of the first switching unit 23, andmoreover, a current inputted to the light emission unit 19 is reduced.

When the voltage V2 detected by the voltage detection unit 33 is lessthan the reference voltage, the voltage comparison unit 37 increases thelevel of the output voltage V3 of the voltage comparison unit 37. Whenthe level of the voltage inputted to the control terminal Ctl increases,the control unit 21 adjusts the driving signal so as to increase shortenthe turn-on section of the first switching unit 23. Therefore, theoutput current of the trans unit 15 is increased in proportion to anincrease rate of the turn-on section of the first switching unit 23, andmoreover, a current inputted to the light emission unit 19 is increased.

Herein, when the input voltage of the trans unit 15 is changed, thecontrol unit 21 compensates for an error current, which is caused by thechange of the output voltage of the trans unit 15, according to an errorvoltage detected by the error voltage diction unit 31 through theauxiliary winding unit 15A of the trans unit 15, thereby allowing aconstant current to be supplied.

When the output current of the trans unit 15 is changed or the inputvoltage of the trans unit 15 is changed, the error voltage detectionunit 31 detects and supplies an error voltage in order for a constantcurrent to be supplied to the light emission unit 19.

The error voltage detection unit 31 has a structure that receives thefeedback of a voltage for regulating a current from the auxiliarywinding unit 15A of the trans unit 15, and uses a Primary SideRegulation (PSR) scheme.

FIG. 2 is a circuit diagram illustrating the current regulationapparatus of FIG. 1.

Referring to FIG. 2, the trans unit 15 includes a primary winding N1, asecondary winding N2, and the auxiliary winding unit 15A. A first tap ofthe primary winding N1 is connected to an output terminal of therectification unit 13, and a second tap of the primary winding N1 isconnected to a drain of the first switching unit 23. The first switchingunit 23 may be configured with a Bipolar Junction Transistor (BJT) or aMetal Oxide Semiconductor Field Effect Transistor (MOSFET).

The DC output unit 17 is connected to the secondary winding N2 of thetrans unit 15. The DC output unit 17 includes a second diode D2, and afifth capacitor D5 that has one end connected to a cathode of the seconddiode D2 in parallel and another end connected to a ground terminal. Thesecond diode D2 and the fifth capacitor C5 smooth a voltage outputted tothe secondary winding N2 of the trans unit 15 and output the smoothedvoltage.

The error voltage detection unit 31 is connected to the first tap of theauxiliary winding unit 15A of the trans unit 15. The feedback unit 25 isconnected to the second tap of the auxiliary winding unit 15A of thetrans unit 15. A center tap of the auxiliary winding unit 15A of thetrans unit 15 is grounded. A voltage, which has polarity opposite tothat of the secondary winding N2 of the trans unit 15, is induced to thefirst tap of the auxiliary winding unit 15A. A voltage, which has thesame polarity as that of the secondary winding N2 of the trans unit 15,is induced to the second tap of the auxiliary winding unit 15A.

A third diode D3 is connected to the second tap of the auxiliary windingunit 15A. A voltage passing through the third diode D3 is supplied tothe feedback terminal FB and power source terminal Vcc of the controlunit 21 through the feedback unit 25.

The feedback unit 25 includes a plurality of voltage-dividing resistorsR8 and R9, and feeds back a voltage-divided voltage that has passedthrough the voltage-dividing resistors R8 and R9.

The voltage detection unit 33 of the error voltage detection unit 31includes first and second time constant circuits 33A and 33B. The firsttime constant circuit 33A includes a first resistor R1 connected to thefirst tap of the auxiliary winding unit 15A at one end thereof, and afirst capacitor C1 connected to another end of the first resistor R1 inparallel. The second time constant circuit 33B includes a secondresistor R2 serially connected to the other end of the first resistor R1at one end thereof, and a second capacitor C2 connected to another endof the second resistor R2 in parallel. The first time constant circuit33A stores a voltage induced to the auxiliary winding unit 15A of thetrans unit 15, and discharges the stored voltage. A time constant of thefirst time constant circuit 33A may be one to one hundred times greaterthan the turn-on time of the first switching unit 23.

Herein, a voltage, which is applied to the first tap of the auxiliarywinding unit 15A, is inputted by a turns ratio of the secondary windingN2 and first auxiliary winding N4 of the trans unit 15, and moreover isinputted by a turns ratio of the primary winding N1 and first auxiliarywinding N4 of the trans unit 15. The voltage inputted to the first tapmay be regulated in proportion to the level of the output voltage of thetrans unit 15 by adjusting the turns ratio. A voltage, which is appliedto the second tap of the auxiliary winding unit 15A, is inputted by aturns ratio of the secondary winding N2 and second auxiliary winding N3of the trans unit 15, and moreover may be regulated in proportion to thelevel of the output voltage of the trans unit 15 by adjusting the turnsratio.

The first resistor R1 is connected to the first diode D1 having agrounded anode, and when a control voltage is a negative voltage, thefirst diode D1 is connected to the ground terminal.

The second time constant circuit 33B stores an output voltage of thefirst time constant circuit 33A, and discharges the stored voltage. Inthis case, the voltage discharged by a time constant may be outputted asa smoothed voltage V2.

FIG. 3 is a diagram for describing an operation of the first timeconstant circuit in a turn-on section of the first switching unit 23.FIG. 4 shows a voltage applied to the first time constant circuit. FIG.5 is a partially enlarged diagram of FIG. 4.

In FIG. 4, a voltage applied to the first time constant circuitincreases linearly during the turn-on section of the first switchingunit 23 as in FIG. 3. Herein, for example, when an operation switchingfrequency of the first switching unit 23 is about 70 KHz, a time takenuntil the input voltage of the trans unit 15 is applied to the secondtap of the auxiliary winding unit 15A is shorter than about 14.28 us.Herein, by adjusting values of the first resistor R1 and first capacitorC1 of the first time constant circuit 33A, a time constant is set to oneto one hundred times greater than that of the turn-on section of thefirst switching unit 23, and thus, a linearly increased voltage V1 isobtained. The first capacitor C1 is charged as in FIG. 5.

Herein, Vc=(N4/N1)*Vin.

FIG. 6 is a diagram for describing an operation of the first timeconstant circuit in a turn-off section of the first switching unit.FIGS. 7 and 8 are graphs showing the voltage of the first time constantcircuit.

Referring to FIGS. 2 and 6, when the first switching unit 23 is turnedoff, the output voltage of the trans unit 15 is applied to the windingof the auxiliary winding unit 15A, in which case an expended time may beless than about 14.28 us. The voltage Vc applied to the first timeconstant circuit 33A is linearly reduced by the time constant value ofthe first time constant circuit 33A as in the graph of FIG. 7.

Herein, Vc=−(N4/N2)*Vo.

FIG. 8 is a diagram showing a voltage waveform of the first timeconstant circuit 33A in the turn-on and turn-off sections of the firstswitching unit. A discharging time T1 of the second time constantcircuit 33B may be shorter than the turn-off time of the first switchingunit 23.

Herein, the area of a region A1 in FIG. 8 may be obtained in theturn-off section of the first switching unit 23, and by using the areaof the region A1 information regarding an output current Io of the transunit 15 may be obtained with Equation (1) below.

$\begin{matrix}{{{\frac{N_{1}}{N_{2}}V_{0}} = {L_{M}\frac{\mathbb{d}i_{0}}{\mathbb{d}t}}}{i_{0} = {\frac{N_{1}}{N_{2}L_{M}}{\int{V_{0}{\mathbb{d}t}}}}}} & (1)\end{matrix}$

Referring to FIG. 2, the voltage of the first time constant circuit 33A,namely, a triangular waveform signal is outputted as a constant DCvoltage due to the time constant value of the second time constantcircuit 33B. That is, the second time constant circuit 33B adjusts thevalue of the second resistor R2 and the value of the second capacitor C2to output an input voltage as a smoothed DC voltage.

Therefore, by adjusting the time constant value of the second timeconstant circuit 33B and the time constant value of the first timeconstant circuit 33A, an output current of the trans unit 15 may bedetected.

The output voltage V2 of the second time constant circuit 33B isoutputted to the voltage comparison unit 37. At this point, the secondswitching unit 35 is turned off.

The second switching unit 35 may be configured with a BJT or a MOSFET.

A third resistor R3 is connected to a drain of the second switching unit23, and connected to an output terminal of the second time constantcircuit 33B.

A waveform of the output voltage V2, which is generated when the firstswitching unit 23 is turned on, is generated as in the voltage waveformof FIG. 5. At this point, the second switching unit 35 is simultaneouslyturned on, and thus, the output voltage V2 is discharged by the thirdresistor R3. A waveform of the output voltage V2, which is generatedwhen the first switching unit 23 is turned off, is generated as in FIG.7. At this point, the second switching unit 35 is simultaneously turnedoff, and thus, the output voltage V2 is inputted to the voltagecomparison unit 37. Moreover, the level of the voltage V2 is not changedby the change of an input voltage due to the third resistor R3, and thevoltage V2 is inputted to the voltage comparison unit 37 due to thechange of an output current. Therefore, the output current is notchanged in spite of the change of the input voltage, and thus, aconstant current is outputted.

The voltage comparison unit 37 includes a voltage-dividing unit 37A, acomparison unit 37B, and a gain adjustment circuit 37C. Thevoltage-dividing unit 37A includes fourth and fifth resistors R4 and R5,and voltage-divides the output voltage V2 of the voltage detection unit33 with the fourth and fifth resistors R4 and R5 to output thevoltage-divided voltage to a reference terminal of the comparison unit37B.

The comparison unit 37B operates as an error amplifier to output anerror voltage V3 to the control terminal Ctl of the control unit 21.

The comparison unit 37B compares an input voltage V2 a with a referencevoltage therein. The comparison unit 37B compares the voltage V2 aoutputted from the second time constant circuit 33B and the referencevoltage therein to output the changed voltage V3 to the control terminalCtl of the control unit 21.

An anode of the comparison unit 37B is connected to a ground terminal,and a cathode of the comparison unit 37B is connected to the powersource terminal Vcc of the control unit 21.

The gain adjustment circuit 37C includes a sixth resistor R6 connectedto the voltage-dividing unit 37A, a third capacitor C3 that is connectedbetween the sixth resistor R6 and the cathode of the comparison unit37C, and a fourth capacitor C4 that is connected to the voltage-dividingunit 37A and the cathode of the comparison unit 37B in parallel. Thegain adjustment circuit 37C adjusts a gain of the output voltage V3 ofthe comparison unit 37B, and thus prevents a malfunction due to avoltage having an abnormal frequency.

Therefore, the control unit 21 increases or decreases the turn-onsection of the first switching unit 23 according to the change of thevoltage V3 inputted to the control terminal Ctl, thereby regulating theoutput current of the trans unit 15 without any change.

Herein, when the input voltage Vin of the trans unit 15 rises, thecomparison unit 37B decreases the output voltage V3. On the contrary,when the input voltage Vin of the trans unit 15 drops, the comparisonunit 37B increases and outputs the output voltage V3. The error voltagedetection unit 31 detects an error of an output voltage due to thechange of the input voltage of the trans unit 15, and increases ordecreases the turn-on section of the first switching unit 23.

The auxiliary winding unit 15A detects an error voltage with the errorvoltage detection unit 31 to output the error voltage to the controlterminal Ctl of the control unit 21. Due to this reason, when the errorvoltage is fed back to the feedback terminal FB of the control unit 21,a feedback voltage is required to be increased to about 2.5 V, for whichthe winding number of the auxiliary winding unit 15A is furtherincreased. Due to such limitations, the volume of the trans unit 15 isincreased, and efficiency is entirely reduced. Also, when an errorvoltage is detected to the feedback terminal FB of the control unit 21,the control unit 21 is malfunctioned in controlling the output current,it is difficult to control the voltage of the control terminal Ctl, andthere is a limitation in setting the output current.

FIG. 9 is a circuit diagram illustrating a detailed example of thecomparison unit.

Referring to FIG. 9, in the comparison unit 27B, the input voltage V2 ais inputted to a positive terminal of a comparator 41, and a referencevoltage Vref is inputted to a negative terminal of the comparator 41. Anoutput terminal of the comparator 41 is connected to a base of aswitching element 42, a collector of the switching element 42 isconnected to the cathode of the comparison unit 37B, and an emitter ofthe switching element 42 is connected to the anode of the comparisonunit 37B.

To provide a constant current controlling operation with reference toFIG. 2, when the output current of the trans unit 15 is changed, thevoltage V2 that is detected from the voltage detection unit 33 throughthe auxiliary winding unit 15A is increased. The voltage comparison unit37 compares the reference voltage and the detected voltage V2, and whenthe detected voltage V2 is higher than the reference voltage, thevoltage comparison unit 37 outputs a decreased voltage to the controlterminal Ctl of the control unit 21. The control unit 21 decreases theturn-on section of the first switching unit 23 in proportion to thedecreased voltage that is inputted to the control terminal Ctl of thecontrol unit 21.

When the output current of the trans unit 15 is changed, the voltage V2that is detected from the voltage detection unit 33 through theauxiliary winding unit 15A is decreased. The voltage comparison unit 37compares the reference voltage and the detected voltage V2, and when thedetected voltage V2 is lower than the reference voltage, the voltagecomparison unit 37 outputs an increased voltage to the control terminalCtl of the control unit 21. The control unit 21 increases the turn-onsection of the first switching unit 23 in proportion to the increasedvoltage that is inputted to the control terminal Ctl of the control unit21.

Moreover, the change of the output current of the trans unit 15 may beidentically applied even in the change of the input voltage Vin of thetrans unit 15.

Therefore, the current regulation apparatus adjusts the turn-on sectionof the first switching unit 23 by an error value detected by the errorvoltage detection unit 31, according to the change of the input voltageVin of the trans unit 15 or the change of the output current Io, therebyallowing the output current of the trans unit 15 to be supplied as aconstant current.

Moreover, when a voltage detected from the voltage detection unit 33 ishigher than or lower than the reference voltage, the comparison unit 37Bof the voltage comparison unit 37 inputs/disconnects a voltage, appliedto the power source terminal Vcc of the control unit 21, to/from thecontrol terminal Ctl of the control unit 21, and thus controls theturn-on section of the first switching unit 23.

The above-described current regulation apparatus may be applied to apower module of each of lighting systems such as backlight units,various kinds of display devices, headlamps, streetlamps, indoor lamps,outdoor lamps, signal lights, and lighting lamps.

According to embodiments, an opto coupler can be removed.

According to embodiments, an integrated circuit for controlling aconstant current can be removed.

According to embodiments, the volume of a trans unit can be reduced.

According to embodiments, by adjusting an error of an output voltage ofthe trans unit, an output current can be stably supplied.

According to embodiments, the reliability of a current regulationapparatus for LED can be improved.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

The invention claimed is:
 1. A current regulation apparatus comprising:a trans unit comprising an auxiliary winding unit; a first switchingunit controlling an operation of the trans unit; an error voltagedetection unit and a feedback unit connected to the auxiliary windingunit of the trans unit; and a control unit adjusting a turn-on sectionof the first switching unit according to an output voltage of a voltagecomparison unit, wherein the error voltage detection unit includes: avoltage detection unit detecting a voltage induced to the auxiliarywinding unit, the voltage comparison unit comparing a voltage detectedby the voltage detection unit and a reference voltage, and the errorvoltage detection unit and the feedback unit are connected to both endsof the auxiliary winding unit, respectively.
 2. The current regulationapparatus according to claim 1, comprising a light emission unitcomprising a plurality of Light Emitting Diodes (LEDs) which emit lightby a voltage outputted to a secondary side of the trans unit.
 3. Thecurrent regulation apparatus according to claim 1, comprising a secondswitching unit receiving a signal, inputted to an output terminal of thevoltage detection unit and the first switching unit, to perform aswitching operation.
 4. The current regulation apparatus according toclaim 3, comprising a resistor connected to a drain of the secondswitching unit and, an output terminal of the voltage detection unit,the resistor preventing an input voltage from being transferred to thevoltage comparison unit by turn-on of the first switching unit.
 5. Thecurrent regulation apparatus according to claim 3, wherein the secondswitching unit and the first switching unit are simultaneously turned onor turned off by a driving signal of the control unit.
 6. The currentregulation apparatus according to claim 3, wherein each of the secondswitching unit and the first switching unit comprises a Bipolar JunctionTransistor (BJT) or a Metal Oxide Semiconductor Field Effect Transistor(MOSFET).
 7. The current regulation apparatus according to claim 1,comprising a feedback unit connected to a tap of the auxiliary windingunit to feed back an output voltage of the trans unit to a feedbackterminal of the control unit.
 8. The current regulation apparatusaccording to claim 1, wherein the voltage detection unit comprises: afirst time constant circuit connected to the auxiliary winding unit; anda second time constant circuit smoothing an output voltage of the firsttime constant circuit.
 9. The current regulation apparatus according toclaim 1, wherein the voltage comparison unit comprises: a comparisonunit comparing an output voltage of the voltage detection unit and areference voltage therein to output a signal to a control terminal ofthe control unit; and a gain adjustment circuit adjusting a gain of anoutput voltage of the comparison unit.
 10. The current regulationapparatus according to claim 9, wherein, a tap of the auxiliary windingunit is connected to a power source terminal of the control unit througha diode, and the power source terminal of the control unit is connectedto an output terminal of the comparison unit of the voltage comparisonunit.
 11. The current regulation apparatus according to claim 1, whereina voltage proportional to a voltage, induced to a secondary side of thetrans unit, is induced to the auxiliary winding unit.
 12. The currentregulation apparatus according to claim 1, wherein the control unitcomprises a power factor compensation circuit.
 13. The currentregulation apparatus according to claim 1, wherein, a Direct Current(DC) output unit is connected to a secondary winding of the trans unit,and the DC output unit comprises a second diode, and a fifth capacitorconnected to a cathode of the second diode in parallel, and having othergrounded end.
 14. The current regulation apparatus according to claim 1,wherein, the error voltage detection unit is connected to a first tap ofthe auxiliary winding unit of the trans unit, the feedback unit isconnected to a second tap of the auxiliary winding unit, a center tap ofthe auxiliary winding unit is grounded, a voltage having polarityopposite to a secondary winding of the trans unit is induced to thefirst tap of the auxiliary winding unit, and a voltage having the samepolarity as the secondary winding of the trans unit is induced to thesecond tap of the auxiliary winding unit.
 15. A current regulationapparatus comprising: a trans unit comprising an auxiliary winding unit;a first switching unit controlling an operation of the trans unit; avoltage detection unit detecting a voltage induced to the auxiliarywinding unit; a voltage comparison unit comparing a voltage detected bythe voltage detection unit and a reference voltage; a control unitadjusting a turn-on section of the first switching unit according to anoutput voltage of the voltage comparison unit; a light emission unitcomprising a plurality of Light Emitting Diodes (LEDs) which emit lightby a voltage outputted to a secondary side of the trans unit; a feedbackunit connected to a tap of the auxiliary winding unit to feed back anoutput voltage of the trans unit to a feedback terminal of the controlunit; and an error voltage detection unit and the feedback unitconnected to the auxiliary winding unit of the trans unit, wherein theerror voltage detection unit and the feedback unit are connected to bothends of the auxiliary winding unit, respectively.
 16. The currentregulation apparatus according to claim 15, comprising a secondswitching unit receiving a signal, inputted to an output terminal of thevoltage detection unit and the first switching unit, to perform aswitching operation.
 17. The current regulation apparatus according toclaim 16, comprising a resistor connected to a drain of the secondswitching unit and an output terminal of the voltage detection unit, theresistor preventing an input voltage from being transferred to thevoltage comparison unit by turn-on of the first switching unit.
 18. Thecurrent regulation apparatus according to claim 15, wherein the voltagedetection unit comprises: a first time constant circuit connected to theauxiliary winding unit; and a second time constant circuit smoothing anoutput voltage of the first time constant circuit.